People like Richard Branson have it because they have been knighted. In the United States, and probably other places as well, we use it to refer to somebody respectfully when it's somebody with a higher position that we don't know well or when we're getting somebody's attention in the street, et cetera. The female version of that is "ma'am".

British English here! Hi! In England, we use it to mean three main things. "Sir" meaning a formal title used to address people who have been knighted and a few other offices in our country, including OBE's (Order of the British Empire). There are several other titles "Sir" is used for including Baronet, & Knighthoods. To receive the title "Sir" to use in Britain, you must be a titled knight or hold another office connected to the word. This is the case with Sir Richard Branson. He was included in the 1999 Honours List and formally knighted by Prince Charles in 2000. Other examples of this kind of "Sir" are Sir Lewis Hamilton, Sir Sean Connery & Sir Bill Gates. Another way you might use "Sir" is to refer to a male teacher. For example, you may be taught by Mr Brown, but you may call him sir instead of saying his name every time. ("Sir, can I have some help" or "Mr Brown, can I have some help" both work in this case). The final way is if you were checking into a hotel or at a shop, the assistant (or manager) may refer to a male customer as sir. For example, "Would you like a bag, Sir?" I hope this helps!

Hi Dingui. The term ‘sir’ is usually used when you want to respectfully refer to a male figure.

Sir is usually used to address someone in an authoritative position, or that has specific importance or a title eg: Sir Isaac Newton

The media respect him because he is a well known public figure in society with an elite social status